A discovery could lead to new ways to treat a particularly aggressive form of childhood brain tumour.
A key gene is to blame
Craniopharyngioma tumours, responsible for one in 10 childhood brain tumours, cause severe headaches, vomiting, disturbed vision and growth defects.
An Aston University team found the condition is linked to a mutation in a gene called catenin, which helps regulate development before birth.
Details will be published in the Journal of Neurooncology.
Craniopharyngioma tumours are usually diagnosed in babies and very young children.
The Aston team found the catenin gene was altered in nearly all cases they studied.
They believe their work establishes the problem that leads to the development of the tumours occurs at the earliest stages of life.
Lead researcher Dr Eric Adams said: "Normally, the catenin gene is switched on very briefly, carries out its duties in the cell, and then switches off at exactly the right moment.
"We believe that the mutations cause the gene to be switched on for far too long and this can lead to too much cell growth.
"It's a bit like the accelerator button on a train getting jammed at maximum and the engine races out of control."
Difficult to treat
Doctors believe that when symptoms first appear the tumour is growing quite fast and this makes it very difficult to treat, even by modern surgical procedures.
Craniopharyngiomas are 'sticky' and tend to attach to surrounding brain tissue.
This makes it very difficult to remove the whole tumour during surgery without damaging the rest of the brain.
Consequently, residual pieces of the tumour are often left behind, which can then re-grow.
Another problem for many of these children is that the tumour grows in an area of the brain that controls the endocrine glands.
Many young patients suffer from inadequate growth and delayed puberty because of hormone deficiency and require life-long hormone replacement therapy.
Dr Adams said: 'We are very excited by what we have found because it means that for the first time new treatments can be developed to be directed against these gene defects.
"One approach might be to devise methods to knock out the defective catenin gene by adding an 'anti gene', something that prevents the gene being switched on into the diseased cells."
The research was funded by the Association for International Cancer Research (AICR).
'Adds to understanding'
Derek Napier, AICR chief executive, said: "Even though craniopharyngioma is a very serious disease, very few laboratory studies on its biochemistry have to date been performed.
"I am convinced this discovery will lead to new ways to tackle what is undoubtedly a particular aggressive and debilitating disease."
Dr Darren Hargrave, a child cancer specialist at the Royal Marsden Hospital, says: "This interesting research adds to the understanding of the genetic background of craniopharyngiomas.
"It confirms previous findings that mutations of the B-catenin gene are associated with a particular type of this benign brain tumour.
"This type of research is important as a better insight into the biological development of brain tumours may in the future translate into improved treatments."